Wireless communication systems allow wireless devices to communicate without the necessity of wired connections. Because wireless systems have become so integrated into daily life, there is a growing demand for wireless communication systems that support multimedia services, such as speech, audio, video, file and Web downloading, and the like. Various wireless communication protocols and transmission control mechanisms have been developed to meet the growing demands of multimedia services over wireless communication networks and to improve the performance of these multimedia services.
In wireless communication systems, multiple-input and multiple-output (MIMO), a form of smart antenna technology, involves the use of multiple antennas at both the transmitter and receiver to improve communication performance. Beamforming, a signal processing technique used for directional signal transmission and/or reception, may be used to improve transmission and reception gains. In beamforming, spatial selectivity is achieved by using adaptive or fixed receive/transmit beampatterns.
Precoding is a generalized beamforming technique used to support multi-layer transmission in MIMO systems. When a receiver has multiple antennas, precoding is used for multi-layer beamforming in order to maximize the throughput performance of a multiple receiver antenna system. When a transmitter has multiple antennas, precoding is used to emit signals from the transmit antennas with independent and appropriate weighting per each antenna such that the link throughput is maximized at the receiver output.
In uplink transmissions, neighboring BSs might suffer from strong interference, especially when a mobile station (MS) or other form of terminal is located at BS cell edges.
The disclosed embodiments are directed to overcoming one or more of the problems set forth above.